1. Field
The present invention relates to a recording medium heating device, a pretreatment liquid coating/drying apparatus, and a printing system.
2. Description of the Related Art
In printing systems, such as rotary presses, in order to evaporate the solvent of ink printed on a sheet, there is a technique in which a sheet is dried by multiple heating rollers provided on the conveying path of the sheet; see, for example, JP-H10-202839-A.
In addition, image recording of an inkjet method is becoming increasingly popular these days because of its advantage that colorization can be easily realized, in addition to its advantages of low noise and low running cost. However, when an image is formed on a recording medium which is not manufacturer-specified paper, problems related to initial image quality such as image blur, image concentration change, color tone change, image show-through, etc., occur. In addition, problems related to robustness of images such as water resistance, weather resistance, etc., occur.
In order to solve this problem, a treatment liquid that has a function to agglomerate the ink is applied immediately before the ink droplets are ejected to the sheet (recording medium), thereby improving the image quality. In a case where the pretreatment liquid is applied, it is necessary to dry the sheet before the ink is ejected. Herein, in a drying device that dries the sheet with multiple heating rollers provided on the conveying path of the sheet, there is a risk of cockling occurring, that is a wave-shaped deformation of the sheet upstream of and/or downstream of the drying device.
Accordingly, for example, in JP-2012-035566-A, in order to prevent the occurrence of cockling, after the ink lands on the recording medium in the printing operation, a drying device having a seasoning unit sprays heated moist air on the recording medium.
A possible drawback of the drying device with the seasoning unit described above is that, because multiple processes are required, the configuration of the device is complicated and large scale. In addition, although since the above-described device disposes a countermeasure for the cockling during printing, the cockling is not taken into account in starting in the above-described drying device.